Those who have been following the debate over global climate change are undoubtedly familiar with the dendroclimatology “hockey stick” plot, perhaps made most famous by Al Gore when he showed one version of it in his film An Inconvenient Truth. The scientific criticism of the plot has mostly been led by Stephen McIntyre and Ross McKitrick, who engaged in a persistent effort to establish their credibility in what was for them a new field. They received a significant boost when physicist Richard Muller expressed agreement with their criticisms in 2004, and it has forced re-examination of one result that has perhaps become too iconically associated with climate-change research.

Muller was one of several who testified at a Congressional hearing on climate change last week that had been called by Republican leaders of the Science & Technology Committee who are skeptical about the reliability of climate research. The comments of the six witnesses can be read here and include many observations that have previously been made. What is attracting most interest, though, was the report by Muller showing that preliminary results of his Berkeley Earth Surface Temperature Project show warming trends that are similar to those found by other groups.

Some of those attempting to politicize climate research have hinted that Muller has somehow betrayed them. But what he has really done is his job as a physicist: criticizing work when it deserves it, adding his own piece to the collective puzzle, and accepting the scientific results whatever they happen to be.